Chipset provides serial interface for HD broadcast

A 3Gbit/s serial digital interface chipset is for use with 1080p high-definition broadcast video, operating at 60frame/s over coaxial cable.

National Semiconductor has introduced a 3Gbit/s (3G) serial digital interface (SDI) chipset that provides a low jitter transmission for 1080p high-definition (HD) broadcast video of 60frame/s over a single coaxial cable.

National's 3G chipset, which includes the LMH0344 adaptive cable equaliser, LMH0346 reclocker and LMH0302 cable driver, is well-suited for serial routing and distribution applications as well as a wide range of video production and processing applications.

National has also introduced a 3G multi-rate SDI serialiser and deserialiser chipset.

Each product in National's 3G chipset meets the requirements of the new Society of Motion Picture and Television Engineers (SMPTE) 424M broadcast video standard, which supports serial transmission of higher resolution 1080p video.

Among the benefits promised by these products include a 3G adaptive equaliser which guarantees less than 0.3 units interval (UI) of alignment jitter, a 3G SDI reclocker which is claimed to be the industry's smallest operating at lowest power and lowest jitter, and a cable driver that offers excellent output-return loss, low additive jitter and a power-saving standby mode.

The 3G chipset is backward compatible with National's existing HD-SDI product family.

National's chipset is a complete 3Gbit/s SDI system including equaliser, reclocker, cable driver, serialiser and deserialiser.

The chipset adds to National's expanding portfolio of 3G SDI products - including the LMH0340 serialiser and LMH0341 deserialiser - to deliver a complete end-to-end transmission system for SMPTE 424M.

National also offers a complete family of signal-conditioning products, including the DS25BR100/110/120 LVDS buffers, capable of operation up to 3.125Gbit/s.

The LMH0344 automatically adapts and equalises signals from 143Mbit/s to 2.97Gbit/s.

It has a low output-alignment jitter across cable lengths allowing hardware designers more headroom for designing within system jitter budgets.

The LMH0344 guarantees less than 0.3UI of output jitter from zero to 100m of Belden 1694A coaxial cable at 2.97Gbit/s.

It equalises 120m of cable at 3G rates, 140m at HD rates and 350m at SD rates.

The device typically consumes 285 mW of power from a single 3.3V supply and is packaged in a 16-pin LLP package that is fully backward compatible with National's LMH0044 HD-SDI equaliser.

The LMH0346 3G SDI reclocker automatically detects and retimes the incoming signal to reduce high-frequency jitter.

It is thought to be the only discrete single-channel 3G SDI reclocker without an input mux.

By removing the input mux, National reduced the pin-count to one-third of competitive devices and the package size by one-half.

Compared with competitive products that require one reference crystal for each individual reclocker, the LMH0346 is capable of sharing a single 27MHz reference across multiple devices, which further reduces board area and system costs.

Dual differential outputs and an optional data-rate clock maximise designer flexibility.

The device typically consumes 390 mW from a single 3.3V supply and is housed in a tiny 20-pin TSSOP package that is backward compatible with National's LMH0046 HD-SDI reclocker.

The LMH0302 drives 75Ohm transmission lines at data rates from DC to 2.97Gbit/s.

A power-saving enable pin allows the user to disable the output driver to reduce power consumption to 76mW in standby mode.

With driver enabled, power consumption is 162mW at 3G and HD data rates using a single 3.3V supply.

The LMH0302 provides two selectable slew rates for compliance with SMPTE 259M and SMPTE 424M/292M.

The device is housed in a 16-pin LLP package that is backward compatible with National's LMH0002SQ HD-SDI cable driver.

The 3G SDI chipset will begin sampling in Q2 2007.

The LMH0344 costs US $31, the LMH0346 costs $35 and the LMH0302 costs $11, each in quantities of 100.

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